Problem: What is the next term of the geometric sequence? $189,63,21,$
Answer: Each term is a third of the term before it. In other words, each term is ${\dfrac13}$ times the term before it. ${\times \dfrac13\,\curvearrowright}$ ${\times \dfrac13\,\curvearrowright}$ $189,$ $63,$ $21$ The next term is $21\cdot{\dfrac13}=7$.